day07_1.js

function regexVar() {
  /*
   * Declare a RegExp object variable named 're'
   * It must match a string that starts and ends with the same vowel (i.e., {a, e, i, o, u})
   */
  //  ^ => first item matches:
  // () => stores matching value captured within
  // [aeiou] => matches any of the characters in the brackets
  // . => matches any character:
  // + => for 1 or more occurrances (this ensures str length > 3)
  // \1 => matches to previously stored match.
  // \2 looks for matched item stored 2 instances ago
  // \3 looks for matched item stored 3 ago, etc
  //  $ ensures that matched item is at end of the sequence

  let re = /^([aeiou]).+\1$/;

  /*
   * Do not remove the return statement
   */
  return re;
}

const re = regexVar();
const s = "abcda";

console.log(re.test(s));